1. Field of the Invention
This invention relates to slide fasteners having stringers formed from a continuous coupling element secured within a folded edge of a support member or tape with head portions of the continuous coupling element extending from openings in the folded edge.
2. Description of the Prior Art
In commercially available slide fastener stringers utilizing a continuous coupling element such as a spiral coupling element secured to one edge of a carrier or support tape, the continuous coupling element is usually secured to the edge of the tape by sewing or by weaving the coupling element to the tape. The prior art, as exemplified in U.S. Pat. Nos. 1,557,303, 1,609,487, 1,933,290, 1,937,297, 2,018,099, 2,296,880, 3,430,304 and 3,517,422 and French Pat. No. 1,135,269, discloses a number of slide fasteners having continuous coupling elements secured within a fold of a support member wherein head portions of the coupling element extend from slots across the folded edge of the support member. Additionally, French Pat. No. 452,527 discloses a fastener with a spiral secured by strips of material formed at an angle across a folded edge of a strip. The commercial employment of slide fasteners with continuous coupling elements secured in a fold of a tape has not been significant compared to fasteners wherein the coupling elements are woven or sewn to textile tapes despite the obvious cost advantage of low cost strips such as synthetic polymer or paper strips compared to woven textile tapes. This failure can be attributed to deficiencies in the prior art, such as breakage or tearing of the strap portions of the support member folded over the coupling elements, inferior support or instability for the coupling element, inability to withstand high slider forces, excessive difficulty in slider operation, etc.,
Various other types of slide fasteners have been disclosed as including bead cords secured to a tape adjacent a coil fastener element, such as in U.S. Pat. Nos. 2,497,821, 2,942,338 and 3,002,245; or as including various other cords, braids or strips secured together with continuous coupling elements to tapes, such as in U.S. Pat. No. 3,015,868 and No. Re. 26,086.